EN ISO 10101-2:1998
(Main)Natural gas - Determination of water by the Karl Fischer method - Part 2: Titration procedure (ISO 10101-2:1993)
Natural gas - Determination of water by the Karl Fischer method - Part 2: Titration procedure (ISO 10101-2:1993)
The principle of the method specified is passing a measured volume of gas through a cell containing a relatively small volume of absorbent solution. Water in the gas is extracted by the absorbent solution and subsequently titrated with Karl Fischer reagent. The design of the cell and the absorbent solution are chosen so as to ensure efficient collection of the water at the high flowrates necessary. Is applicable to water concentrations between 5 mg/cm^3 and 5000 mg/cm^3.
Erdgas - Bestimmung des Wassergehaltes nach Karl Fischer - Teil 2: Titrimetrisches Verfahren (ISO 10101-2:1993)
Dieser Teil von ISO 10101 beschreibt ein titrimetrisches Verfahren zur Bestimmung des Wassergehaltes in Erdgas. Die Volumina werden in Kubikmetern angegeben und beziehen sich auf eine Temperatur von 273,15 K (0 °C) und einem Druck von 101,325 kPa (1 atm). Dieses Verfahren gilt für Wasseranteile zwischen 5 mg/m3 und 5000 mg/m3).
Gaz naturel - Dosage de l'eau par la méthode de Karl Fischer- Partie 2: Méthode titrimétrique (ISO 10101-2:1993)
La présente partie de l'ISO 10101 prescrit une méthode titrimétrique pour le dosage de l'eau contenue dans le gaz naturel. Elle est applicable à des concentrations d'eau comprises entre 5 mg/m3 et 5 000 mg/m3. Les volumes exprimés en mètres cubes sont ramenés à une température de 273,15 K (0 °C) et une pression de 101,325 kPa (1 atm).
Zemeljski plin - Določevanje vode po Karl-Fischerjevi metodi - 2. del: Titracijski postopek (ISO 10101-2:1993)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2000
=HPHOMVNLSOLQ'RORþHYDQMHYRGHSR.DUO)LVFKHUMHYLPHWRGLGHO 7LWUDFLMVNL
SRVWRSHN ,62
Natural gas - Determination of water by the Karl Fischer method - Part 2: Titration
procedure (ISO 10101-2:1993)
Erdgas - Bestimmung des Wassergehaltes nach Karl Fischer - Teil 2: Titrimetrisches
Verfahren (ISO 10101-2:1993)
Gaz naturel - Dosage de l'eau par la méthode de Karl Fischer- Partie 2: Méthode
titrimétrique (ISO 10101-2:1993)
Ta slovenski standard je istoveten z: EN ISO 10101-2:1998
ICS:
75.060 Zemeljski plin Natural gas
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERNATIONAL
IS0
STANDARD
10101~2
First edition
1993-I o-01
Natural gas - Determination of water by
the Karl Fischer method -
Part 2:
Titration procedure
Gaz na turel - Dosage de l’eau par la m&hode de Karl Fischer -
Partie 2: Mb thode titrim6 trique
Reference number
IS0 101012:1993(E)
IS0 10101-2:1993(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 10101-2 was prepared by Technical Committee
ISOTTC 193, Natural gas, Sub-Committee SC 1, Analysis of natural gas.
IS0 10101 consists of the following parts, under the general title Natural
- Determination of water by the Karl Fischer method:
gas
- Part 7 : Introduction
- Part 2: Titration procedure
- Part 3: Coulometric procedure
Annex A forms an integral part of this part of IS0 101011
0 IS0 1993
All rights reserved. No part of this publication may be reproduced or utilized in any form or
by any means, electronic or mechanical, including photocopying and microfilm, without per-
mission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-121 1 Geneve 20 l Switzerland
Printed in Switzerland
INTERNATIONAL STANDARD IS0 10101-2:1993(E)
Natural gas - Determination of water by the Karl
Fischer method -
Part 2:
Titration procedure
WARNING - Local safety regulations must be taken into account, when the equipment is located
in hazardous areas. Due to the toxicity and odour of pyridine, the user should ensure that there is
adequate ventilation.
IS0 101 Ol-3:1993, Natural gas - Determination of
1 Scope
water by the Karl Fischer method - Part 3:
Coulometric procedure.
This part of IS0 10101 specifies a titrimetric pro-
cedure for the determination of water content in na-
tural gas. Volumes are expressed in cubic metres at
3 Principle
a temperature of 273,15 K (0 “C) and a pressure of
101,325 kPa (1 atm). It applies to water concen-
A measured volume of gas is passed through a cell
trations between 5 mg/m3 and 5 000 mg/m3.
containing a relatively small volume of absorbent sol-
ution. Water in the gas is extracted by the absorbent
solution and, subsequently titrated with Karl Fischer
reagent. The design of the cell and the absorbent
solution are chosen so as to ensure efficient collection
of the water at the high flowrates necessary.
2 Normative references
The principle and chemical reactions of the Karl
The following standards contain provisions which,
Fischer method are given in IS0 IOIOI-1:1993,
through reference in this text, constitute provisions
clauses 3 and 4; interferences are also described in
of this part of IS0 10101. At the time of publication,
clause 4 of IS0 10101-1.
the editions indicated were valid. All standards are
Clause 4 of IS0 IOIOI-I:1993 describes interfering
subject to revision, and parties to agreements based
substances which may be present in natural gas and
on this part of IS0 10101 are encouraged to investi-
corrections for the interference of hydrogen sulfide
gate the possibility of applying the most recent edi-
and mercaptans.
tions of the standards indicated below. Members of
IEC and IS0 maintain registers of currently valid
International Standards.
4 Reagents
IS0 383: 1976, Laboratory glassware - Interchangea-
ble conical ground joints.
4.1 Kark Fischer reagent, of which the water
equivalent is approximately 5 mg/ml.
IS0 750411984, Gas analysis - Vocabulary.
For most applications, commercially available
NOTE 1
IS0 10101-1:1993, Natural gas - Determination of
Karl Fischer reagent with a water equivalent of approxi-
water by the Karl Fischer method - Part 7: Intro- mately 5 mg/ml has been found adequate. The reagent may
be provided as two solutions which are mixed before use.
duction.
IS0 10101=2:1993(E)
5 Commercial reagents, when aged, may give a slow re-
If required, make up the reagent in the following way.
sponse near the end point.
4.1.1 Components
4.2 Absorbent solution, prepared in the following
way.
4.1.1.1 Methanol, with a water content of less than
0,Ol % (m/m). Use commercially available dry
methanol or methanol dried in the laboratory by one
4.2.1 Components
of the following procedures.
4.2.1.1 Ethylene glycol, with a water content less
a) Place 2 litres of methanol in a two-neck 3 litres
than 0,l % (m/m).
flask and add 10 g of magnesium turnings. Add a
crystal of iodine, connect the flask to a reflux
4.2.1.2 Sulfur dioxide, liquefied and dry.
condenser and leave overnight. Next day, add a
further 5 g of magnesium turnings and reflux for
4.2.1.3 Pyridine, an hydrous.
1 h. Connect the top of the reflux condenser to a
still head, a double surface condenser and a col-
lection flask. Disconnect the water flow through 4.2.1.4 Karl Fischer reagent, (see 4.1).
the condenser originally used for reflux, and distil
the contents of the flask. Discard the first 150 ml
4.2.2 Preparation
of condensate. Distil the rest into dried 1 litre
flasks. Vent the system through a drying tube Slowly add 20 g of sulfur dioxide (4.2.1.2) to 180 ml
during distillation. of anhydrous pyridine (4.2.1.3) while mixing carefully
(solution A).
b) Dry the methanol over a freshly activated molecu-
To prepare the absorbent solution, add 55 ml of dry
lar sieve’).
ethylene glycol (4.2.1 .I ), 55 ml of Karl Fischer reagent
(4.2.1.4) and 73 ml of solution A to a round bottomed
4.1.1.2 2=Methoxyethanol, with a water content of
flask. Boil under reflux for 10 min with a drying tube
less than 0,Ol % (m/m).
on the condenser, and then cool.
NOTE 2 This can be used as an alternative to methanol
(4.1.1 .I), with a lower vapour pressure and therefore less
5 Apparatus
losses due to evaporation during sampling of the gas.
5.1 Karl Fischer apparatus, as described in
4.1.1.3 Pyridine, anhydrous.
annex A.
4.1.1.4 Sulfur dioxide, liquefied and dry.
5.2 Wet-test gas meter, accurate to + 1 % of the
-
4.1 .I 5 Iodine. volume passed.
4.1.2 Preparation
5.3 Guard tube, or Durand bottle, packed with
anhydrous calcium chloride (or another suitable drying
Measure 300 ml of dry methanol (4.1 .I .I) or
agent).
2-methoxyethanol (4.1 .I .2) and 110 ml of anhydrous
pyridine (4.1 .I .3) into a 750 ml conical flask. Slowly
NOTE 6 This is used to prevent back diffusion of water
pass liquid sulfur dioxide (4.1 .1.4) into this solution,
vapour from the gas meter to the titration cell.
mixing carefully until the increase in weight is 43 g.
Cool this solution in a freezing mixture. When cool,
5.4 Titration cell, as shown in figureA.l.
add sufficient iodine (4.1 .I .5) to give a permanent light
brown colour. Then add 63 g of iodine and swirl until
dissolved. Make up to 500 ml with dry methanol or
5.5 Glass syringe, of 20 ml.
2-methoxyethanol. Leave standing in the stoppered
conical flask for 24 h before use.
NOTE 7 Absorbent solution is most easily added to and
removed from the cell by means of a 20 ml graduated
NOTES
syringe with a 6 % (Luer) fitting and hypodermic needles of
suitable length and I mm to 2 mm bore.
3 If required, the reagent may be diluted with pyridine.
5.6 Syringe, with a fixed needle, of 10 ~1, for
4 For the determination of very small amoun ts of water,
is preferable to use freshly p repared rea gent. standardization of the Karl Fischer reagent.
1) Molecular sieves of type 4A (0,4 nm pore diameter) or type 5A (0,5 nm pore diameter) are an examples of a suitable pro-
ducts available commercially. This information is given for the convenience of users of this part of IS0 10101 and does not
constitute an endorsement by IS0 of these products.
I$0 lOtOl-2:7993(E)
V is the volume, in millilitres, of Karl Fischer
6 Standardizatio,n of the Karl Fischer
reagent required for the titration of the
reagent
added water.
Standardize the Karl Fischer reagent daily or before
use, as appropriate.
7 Sampling
See IS0 IOlOl-1:1993, clause 5.
6.1 Using a dry syringe, introduce sufficient absorb-
ent solution (4.2) to cover the electrodes in the ap-
paratus (5.1). Switch on the apparatus and start the 8 Procedure
stirrer motor. Add the Karl Fischer reagent (4.1) until
the needle settles down at a position near zero. When NOTES
this point is reached, cease additions, since additions
9 The apparatus may be used in the laboratory, or outside
of large amounts of reagent will only move the
on the processing plant, with appropriate precautions. The
electrometer about 0,02 V. To achieve maximum
differences between these approaches are described in
sensitivity at this first sta
...
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